In premises to which access is controlled, such as premises containing sensitive information or housing materials or articles that are dangerous or precious, it is becoming more and more frequent to make use of automatic systems for authorizing access, e.g. comprising an identification device that recognizes fingerprints or irises in order to verify whether people attempting to access the premises are entitled to have such access authorized. Such devices provide relatively reliable identification of people submitting themselves to inspection. Nevertheless, on their own such devices cannot prevent a fraudulent person who does not submit to identify checking from penetrating into the controlled-access premises together with some other person whose identity has been checked successfully.
To avoid that drawback, it is common practice to use turnstile-type barriers. Nevertheless, a fraudulent person can jump the barrier so the risk of that person gaining access is still quite high. In addition, that type of barrier restricts the flow of people and is not very practical for users carrying baggage or for people of reduced mobility such as elderly people or people with motor handicaps.
Access monitoring systems are known that use a camera and image processing software for automatically detecting the number of people attempting to access the monitored premises. Such image processing is complex, greedy in computer resources, and relatively lengthy. Furthermore, it is effective only if the person or people attempting to access the premises can be distinguished clearly from the background of the image for processing.
Proposals have been to use identification devices and monitoring systems in airports for monitoring passenger access to departure lounges. To do this, proposals have been made to place lock chambers at the entrances to departure lounges through which passengers are channeled, and that house the identification device and the monitoring device. In order to avoid passengers feeling oppressed in the lock chamber, the lock chamber is defined for the most part by walls that are transparent. Nevertheless, in such an application, the background and the lighting of the lock chamber are not under control, so monitoring devices of the above-mentioned type are difficult to use. In addition, the time taken to process the image is found to be relatively long.